Our objective is the development of an improved, noninvasive technique for early detection of metastases. This proposal is focused on carcinoma of the prostate and is based on two recent developments: (a) the realization that polyamine uptake by the prostate is enhanced many-fold by pretreatment with the ornithine decarboxylase inhibitor, difluoromethylornithine (DFMO) and (b) the rapid development of positron-emission transaxial tomography (PETT) scanning. In the course of this research project, we will determine the conditions for optimal uptake of polyamines by prostate derived tumors in animals. We will develop positron-emitting polyamine analogs and use them to scan tumor bearing animals. We shall subsequently conduct animal toxicity, clearance and dosimetry studies with the radiolabelled polyamines prior to using them for clinical studies. When the animal studies are completed and provided that approval is granted by the appropriate human studies committees, clinical studies are planned to determine the sensitivity and specificity of this scan in patients with carcinoma of the prostate. Finally, if the technology of nuclear magnetic resonance (NMR) imaging expands in the future, to use nuclei other than protons, for imaging (i.e. 19F, 13C, 15N), properly labelled polyamines suggest themselves as "NMR contrast agents" in a similar fashion to their proposed use with the PETT scanner. Appropriate studies to investigate such a possibility will then be conducted.